This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We wish to implement various theoretical methods for the study of structure, fragmentation processes and/or other properties of various classes of biomolecules. We are approaching these problems by using density functional and ab initio calculations as implemented in the Gaussian 03/98 suites of programs. We have these programs running on two quad processor and three dual-processor workstation computers and a single-processor workstation computer that were installed during the previous project period. In addition, Spartan for Linux was installed on the last computer and serves roles in preliminary survey calculations and as a graphical interface. One focus involves a collaborative project using theoretical calculations to investigate structure and fragmentation of the siderophore yersiniabactin and its complexes with ferric and cupric ions. A second collaborative project involves theoretical calculations of various properties of sulfated steroids which are important chemical markers in the mouse and other species.